Using check dam deposits to investigate recent changes in sediment yield in the Loess Plateau, China
Using check dam deposits to investigate recent changes in sediment yield in the Loess Plateau, China
复制标题
利用淤积物调查黄土高原产沙量的近期变化
DOI：
10.1016/j.gloplacha.2017.03.003
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发表时间：
2017
影响因子：
3.9
通讯作者：
Zhang Jia-qiong
中科院分区：
文献类型：
--
作者：
Zhao Tian-yin;Yang Ming-yi;Walling Des E.;Zhang Feng-bao;Zhang Jia-qiong
淤地坝是防治流域水土流失的重要工程措施之一，对减少河流泥沙具有重要作用。此外，在某些情况下，相关的沉积物沉积可以提供关于上游流域沉积物产生率随时间变化的宝贵信息来源。在北方黄土高原的年烟沟流域出口处的淤地坝沉积物中，研究了一个深度为11.325 m的沉积物剖面，流域面积为0.181 km 2。该剖面包含了总共75个可清楚识别的洪水事件偶联的证据，这些偶联对应于1960-1990年期间发生的风暴事件。沉积物的粒度组成（粘土含量）和its 137 Cs的活性和有机质（SOM）含量的变化被用来确定个人的洪水事件偶和事件降雨（特别是极端风暴事件）的记录被用来建立一个年表的个人洪水事件偶。根据库容量曲线和洪水对厚度及泥沙容重资料，计算了各洪水对的产沙量。利用这些数据，年沉积物产量估计范围为零，1965年至9750吨，1984年。从1960年到1990年期间被分为三个不同的阶段，根据证据的变化率的流域内的泥沙生产以上检查坝提供的累积产沙量与累积降水量的双质量图。这些阶段代表了1960 - 1964年、1965 - 1983年和1984 - 1990年这三个时期，其特征是年平均比产沙量分别为26，220 t km− 2 year − 1、5，590 t km− 2 year − 1和19，130 t km− 2 year − 1。这项研究被认为是展示了利用淤地坝沉积物沉积物的潜力，以获得在休息土地利用变化和土壤保持和沉积物控制措施的实施的产沙量的变化的回顾性评估。
Check dams are one of the most important engineering measures for controlling soil and water loss from watersheds and can play a key role in reducing sediment loads in rivers. In addition, the associated sediment deposits can in some circumstances provide a valuable source of information on changing rates of sediment production from the upstream watershed through time. A sediment profile with a depth of 11.325 m was examined within the deposits associated with a check dam at the outlet of the Nianyangou catchment, in the northern Loess Plateau, China, with a drainage area of 0.181 km2. The profile contained evidence of a total of 75 clearly identifiable flood event couplets, which corresponded to storm events occurring during the period 1960–1990. The variability of the grain size composition (clay content) of the sediment and its137Cs activity and organic matter (SOM) content down the profile was used to identify individual flood event couplets and the record of event rainfall (particularly extreme storm events) was used to establish a chronology for the individual flood event couplets. Based on the reservoir capacity curve and information on couplet thickness and sediment bulk density, the sediment yield associated with each flood couplet has been calculated. Using these data, annual sediment yields were estimated to range between zero in 1965 to 9750 t in 1984. The period from 1960 to 1990 was divided into three distinct phases based on evidence for changing rates of sediment production within the watershed above the check dam provided by a double mass plot of cumulative sediment yield versus cumulative precipitation. These phases represent the periods: 1960 to 1964, 1965 to 1983 and 1984 to 1990, which were characterized by mean annual specific sediment yields of 26,220 t km− 2year− 1, 5590 t km− 2year− 1and 19,130 t km− 2year− 1, respectively. This study is seen as demonstrating the potential for using the sediment deposits associated with check dams to obtain retrospective assessments of changes in sediment yield in repose to land use change and the implementation of soil conservation and sediment control measures.